Distributor module and measuring system formed therewith

ABSTRACT

The distributor module serves for distributing electrical power to at least two connected measuring devices (S1, S2) and for forwarding to at least one superordinated electronic data processing unit (NLU) information concerning at least one physical, measured variable transmitted from the connected at least two measuring devices. For this, the distributor module comprises a module housing (100) as well as an electronics module placed within the module housing (100). Additionally present in the distributor module are two or more connection systems, one for each of the measuring devices delivering measured data, with, in each case, a transformer coil placed within the module housing and connected to the electronics module for the forming a data as well as electrical energy transmitting, inductively coupling interface, as well as at least one connection system for the at least one data processing unit, wherein each of the transformer coils is placed, in each case, within a plug connector element composed at least partially of plastic or other synthetic material and serving for forming a plug connector coupling. Moreover, it is provided that the distributor module is applied in a measuring system serving for measuring at least one physical and/or at least one chemical, measured variable.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of pending U.S. application Ser. No.13/126,505 filed on Apr. 28, 2011, which is a National Stage ofPCT/EP2009/063631 filed on Oct. 19, 2009, which claims the benefits ofGerman Application Serial No. 10 2008 053 920.1, filed on Oct. 30, 2008,entitled “Distributor Module and Measuring System Formed Therewith”which are hereby incorporated by reference in their entirety.

The invention relates to a distributor module for distributingelectrical power to at least two connected measuring devices and forforwarding to at least one superordinated electronic data processingunit, especially a data processing unit processing data corresponding tothe measured variable and/or a data processing unit controlling thedistributor module, information concerning at least one physical,measured variable, especially a measured variable serving as a processparameter of an industrial and/or automated process to be monitored,transmitted from the at least two connected measuring devices.Furthermore, the invention relates to a measuring system formed by sucha distributor module.

Such modularly composed measuring systems or individual componentsthereof used in industrial measurement technology are described, forexample, in U.S. Pat. Nos. 6,145,392, 6,366,346, 6,476,520, 6,705,898,6,822,431, 6,898,980, 5,764,928, 5,253,537, US-A 2007/0090963, EP-A 1403 832, EP-A 1 108 992, EP-A 12 21 023, EP-A 062 531, WO-A 08/058,991,WO-A 08/059,019, WO-A 07/124,834, WO-A 05/015130, WO-A 97/35190, DE-A 102006 062184, DE-A 102 18 606 A1, DE-A 103 13 639, WO-A 08/098,954, WO-A08/077,737 or the not prepublished German patent applications102007053223.9, 102007041238.1 or 102008029956.1 and comprise usually asensor module with a measuring transducer—usually a measuring transducerheld on the container, or on the pipeline system, as the case may be,and/or contacting the medium, or at least partially extendingthereinto—for registering at least one measured variable and forproducing at least one primary signal influenced by the measuredvariable, and a sensor electronics connected with the measuringtransducer, in given cases also a sensor electronics formed by means ofa microprocessor, for converting the primary signal delivered by themeasuring transducer into a sensor signal, in given cases also a digitalsensor signal. The measuring transducers are, in such case, oftenexposed to the most difficult operating conditions, such as, forinstance, corrosive chemicals, extreme heat, high pressure and/or strongvibrations, etc.

Measuring systems of the type being discussed further include atransmitter module connected mechanically, especially rigidly, with thesensor module to form a measuring device. The transmitter moduleincludes a transmitter electronics electrically coupled with the sensorelectronics and formed in given cases by a microprocessor for convertingthe sensor signal delivered from the sensor module—in given cases,transmitted from the sensor electronics to the transmitter electronicsvia a galvanic separation point—into the measured values representing atleast one measured variable. For example, the initially mentioned DE-A102 18 606, as well as the German patent applications 102008045314.5,102008029956.1 and 102007041238.1, show in each case a potentiometricmeasuring device with a measuring transducer for registering an, in suchcase potentiometric, measured variable, for instance, a pH value or aredox potential, as well as an inductively coupling interface for theoutput of measured data, which is dependent on a potentiometric measuredvariable, to a transmitter module. In such a case, the measuring deviceshown includes a digital data memory, which is fixedly connected withthe measuring transducer and is insofar an integral component of thesensor module.

The aforementioned galvanically separated interface can be, for example,an inductive interface formed by means of a transformer for feeding thesensor electrical power, especially on the basis of an impressedelectrical current and/or an impressed voltage. The transmission of datasuch as for instance, measured data generated on the part of sensormodule, or configuration and parameter data provided for the sensormodule by the transmitter module, can occur, for example, via the sameinductive interface through a corresponding modulation of the electricalcurrent and/or voltage on the part of each data transmitting module,thus for example, by means of an alternating electrical currentmodulated as regards amplitude and/or frequency and/or by means of analternating voltage modulated as regards amplitude and/or frequency.Construction and operation of such modulators, for instance, using anamplitude- (ASK) or a frequency keying method (FSK) or alsocorresponding demodulators are well known to those skilled in the artand also described, for example, in the initially mentioned Germanpatent applications 102007020823.7 or 102007041237.3 and, respectively,WO-A 08/080,758.

Industrial-strength measuring systems, especially those for operation inexplosion endangered regions, must also furthermore satisfy very highsafety requirements in regard to explosion prevention. In such a case,this especially concerns the certain prevention of sparks or at leastassurring that sparks possibly occurring in the interior of a closedspace have no effects on the environment, in order to safely avoid thepossiblity of potentially triggering an explosion. As explained forthis, for example, also in the initially named EP-A 1 669 726, U.S. Pat.Nos. 6,366,436, 6,556,447 or US-A 2007/0217091, different ignitionprotection types are distinguished in connection with explosionprotection. These are correspondingly manifested in each case also inrelevant standards and norms concerning electrical operating means forexplosion endangered regions. Examples of these standards areUS-American standard FM3600, international standard IEC 60079-18 and thestandards DIN EN 50014 ff. Thus e.g. according to the European Norm EN50 020:1994, explosion protection is met, when devices are embodiedaccording to the therein defined ignition protection type or theprotection class with the name “Intrinsic Safety” (Ex-i). In thisprotection class, the values for the electrical variables, electricalcurrent, voltage and power, in a device each have to lie below apredetermined limit value at any time in each case. The three limitvalues are so selected, that in the case of malfunction, e.g. a shortcircuit, the maximum occurring heat is not sufficient to produceignition sparks. The electrical current is held under the predeterminedlimit values e.g. by resistances, the voltage e.g. by Zener diodes, andthe power through a corresponding combination of current and voltagelimiting components. In the European standard EN 50 019:1994, anotherprotection class is set forth with the name “Increased Safety” (Ex-e).In the case of devices, which are embodied according to this protectionclass, the ignition or explosion protection is achieved by having thespatial distances between two different electrical potentials be solarge that a spark formation cannot occur in the case of malfunction,due to the distance. However, this can lead to circumstances thatcircuit arrangements must have very large dimensions, in order tosatisfy these requirements. In European standard EN 50 018:1994additionally, the ignition protection type “Pressure-ResistantEncapsulation” (Ex-d) is provided as another protection class. Measuringsystems or system modules that are embodied according to this protectionclass must have a pressure resistant housing, through which is assuredthat an explosion occurring in the interior of the housing cannot betransmitted to the external space. Pressure resistant housings areembodied with comparatively thick walls, in order that they have asufficient mechanical strength. In the USA, Canada, Japan and othercountries there are standards comparable to the aforementioned Europeanstandards. Consequently, a transmitter housing, usually hermeticallysealed, most often also pressure, or explosion resistant, in given casesfilled with potting compound for the transmitter electronics, serves toaccommodate the transmitter electronics, while the sensor electronics isarranged in a corresponding, separate sensor housing that also at leastpartially receives the measuring transducer.

Measuring systems of the type being discussed are additionally mostoften integrated into a superordinated electronic data processing systemserving for example, for the automated control of a manufacturing plantcomprising the measuring system, in given cases an electronic dataprocessing system, which is very widely topologically extended, such asfor instance, a data processing system in the form of a process controlsystem (PCS) and/or in the form of a measuring and control loop formedby a programmable logic controller (PLC). Integration is accomplished,in such cases, for example by means of a digital fieldbus, such asPROFIBUS, MODBUS etc., for instance, and/or by means of a radioconnection, to which data processing system measured values produced bythe respective measuring system are forwarded near in time, encapsulatedin given cases in a corresponding telegram. The transmitted measuredvalues can be further processed by means of such data processing systemsand visualized e.g. on monitors as corresponding measurement resultsand/or converted to control signals for other field devices embodied asactuating devices, such as e.g. magnetic-valves etc. Since modernindustrial measuring systems can most often also be directly monitoredand in given cases controlled and/or configured by such controlcomputers; in a corresponding manner, operating data intended for themeasuring device is most often equally dispatched via the aforementioneddata transmission networks, which are hybrid as regards the transmissionphysics and/or the transmission logic. In the data processing system, acomprehensive control and monitoring of the manufacturing plant can thusoccur based on a plurality of measured values, and complex parametersderived therefrom, produced by means of multiple such measuring systems.

Measuring systems of the type being discussed, as shown for example inthe German patent applications 102008029956.1, or 102008045314.5mentioned initially, for the connection of the superordinated dataprocessing system and measuring system, or for the display of measuredvalues, additionally comprise a data processing unit—placed most oftencomparatively widely removed from the transmitter module or themeasuring device formed therewith, or in a less critical environment incomparison to the actual measuring point. This data processing unitadditionally can also be connected to a field bus present in givencases. Connecting cables, usually interposed between the transmittermodule and data processing unit, serve for the connection of therespective measuring device to the correspondingly associated dataprocessing unit, most often likewise embodied as a self-sufficientmeasurement transmitter module, wherein the interfaces of the measuringdevice and data processing unit corresponding with one another as wellas the connecting cable itself usually meet and, respectively, supportthe requirements set by established industrial standards, such as forinstance, EIA-485, EIA-232 or EIA-422, respectively UART (UniversalAsynchronous Receiver Transmitter protocol), as regards construction,circuitry and data coding, respectively, transmission. The connectingcables can furthermore also be “intelligent” connecting cables withintegrated signal processing, such as described for example in the notprepublished German patent application 102007048812.4.

Data processing units of the aforementioned type usually also servesuitably to convert measured values delivered by the measuring device,as well as also parameter values signaling, in given cases, a currentoperating state, or a current configuration of the measuring device, andto condition such values, measured values and parameter values,corresponding to the requirements of downstream data transmissionnetworks, for example, suitably to digitize them or in given cases toconvert them into a corresponding telegram, for example, a fieldbuscapable telegram, and/or to evaluate them and, in given cases, displaythem on-site. For such a purpose, the electronics of such a dataprocessing unit is provided with corresponding transmitter circuits,which further process the sensor measured data received by therespective measuring system into more complex measured values derivedtherefrom and, in given cases, convert such to forwardable telegrams.

Besides the evaluating circuits required for processing and convertingthe measured values delivered by each connected field device, such dataprocessing units most often have also electrical supply circuits servingto supply the connected measuring device with electrical energy andproviding a corresponding internal supply voltage for the entiremeasuring system, in given cases fed directly by the connected fieldbus.A supply circuit can, in such case, for example, associated, in eachcase, with exactly one measuring system and together with the evaluatingcircuit associated with the respective measuring device—for example,unite to form a single data processing unit serving as measurementtransmitter and/or as fieldbus adapter—be accommodated in a sharedelectronics housing of metal and/or plastic or other synthetic material,e.g. formed as top hat rail module. However, it is also quite usual toaccommodate supply circuits and evaluating circuits, in each case, inseparate electronic housings, in given cases spatially remote from oneanother, and to wire them each correspondingly with one another viaexternal lines.

In the case of modularly composed measuring systems, it is additionallyquite usual, as shown for example in U.S. Pat. No. 6,705,898 or EP-A 1108 992, to replace at times one of the two modules on-site afterstart-up of the measuring system with a new, structurally equal one, orat least one of the same type. As shown in the initially mentioned U.S.Pat. No. 6,705,898, for example, the sensor housing and the transmitterhousing therefor can be embodied, in each case, as plug connectorelements complementary to one another for example as described in theinitially mentioned German patent application 102007048812.4 or U.S.Pat. No. 6,705,898, in order to form a pluggable connector coupling withan integrated inductive interface galvanicly isolated from an electricalpoint of view, and connected with one another to be releasable from astructural point of view. Wear susceptible electrical contacts can beavoided by use of such a pluggable connector coupling, since thetransmission of both electrical energy and information between themodules can be accomplished by means of inductive coupling alone. Sincesuch a pluggable connector coupling does not need to have exposed plugcontacts and thus also corresponding openings, the two plug connectorelements and thus also the two modules can be very simple embodiedhermetically sealed. The surface material (for example an electricallynon-conductive plastic or other synthetic material) of the plugconnector elements can be matched to the respective intended use or tothe particular corrosive medium.

The aforementioned inductively coupled interfaces implemented by meansof a pluggable connector coupling are especially suitable for measuringsystems, for instance such as for registering potentiometric measuredvariables, with measuring transducers with a short nominal lifetime,since the same measuring transducer must be regularly replaced as aresult of consumption or wear phenomena. However, a special problem ofconventional measuring systems of the aforementioned type is that themeasuring point implemented therewith—if only temporarily, yetnevertheless recurringly—at times must be taken completely out ofoperation and thus a continuous monitoring of the relevant process orthe plant is not readily assured. Especially for critical applications,this problem can currently be remedied only by the installation of twoor more of such complete measuring systems, which can then be taken outof operation offset in time. However, the application of multiplemeasuring systems for forming a redundant or practically interruptionfree operable measuring point makes the measuring as a whole enormouslymore expensive, both in regards to the acquisition costs and especiallyas well as in regard to the operating costs because of thecorrespondingly increased number of individual components and theincreased calibration and maintenance needs associated therewith.

Consequently, an object of the invention is to improve such modularlycomposed measuring systems having an inductive interface for data andenergy transmission, toward the goal of enabling an interruption freemeasuring operation, also in the case of the application of measuringtransducers that must be recurringly replaced.

For achieving the object, the invention resides in a distributor modulefor distributing electrical power to at least two connected measuringdevices and for forwarding to at least one superordinated electronicdata processing unit, especially one processing data corresponding tothe measured variable and/or controlling the distributor module,information concerning at least one physical, measured variable,especially one serving as a process parameter of an industrial and/orautomated process to be monitored, transmitted from the at least twoconnected measuring devices. The distributor module comprises:

-   -   a module housing, especially one embodied to be water spray        and/or explosion and/or pressure resistant;    -   an electronics module placed within the module housing,        especially an electronics module embodied to be protected from        explosion;    -   a first connection system for a first measuring device        delivering measured data, especially digitized data;    -   a second connection system for a second measuring device        delivering measured data, especially digitized data; as well as    -   at least a third connection system for the at least one data        processing unit;    -   wherein the first connection system and at least the second        connection system, especially each of the three connection        systems, have, in each case, a transformer coil placed within        the module housing and connected to the electronics module for        forming an inductively coupling interface transmitting data,        especially digital data, especially according to the Universal        Asynchronous Receiver Transmitter protocol, as well as        electrical energy, especially an interface transmitting data and        energy simultaneously, especially an interface transmitting        exclusively inductively, and    -   wherein each of the at least two transformer coils is, in each        case, placed within a plug connector element (especially a plug        connector element formed as an integral component of the module        housing) serving to form a plug connector coupling, especially a        releasable plug connector coupling, and composed, at least        partially, especially predominantly or exclusively, of a plastic        or other synthetic material, especially a plastic or other        synthetic material which is at least partially electrically        non-conductive.

Moreover, the invention resides in a measuring system for measuring atleast one physical and/or at least one chemical, measured variable,wherein the measuring system comprises such a distributor module.

According to a first embodiment of the distributor module of theinvention, it is provided that the electronics module includes a controlunit, especially one formed by means of a microprocessor and/or amodifiable logic chip and/or an application specific integrated circuit,for controlling at least the first connection system and the secondconnection system and/or for processing control commands received via athird connection system. Developing this embodiment of the inventionfurther, it is additionally provided that the electronics module has aselective switching circuit, especially one controlled by and/orintegrated into the control unit, for the selective connection of thecontrol unit to at least one of the transformer coils and/or for theselective connection of the third connection system to at least one ofthe transformer coils of the first or second connection system.

According to a second embodiment of the distributor module of theinvention, it is provided that the electronics module includes at leasta first demodulator for separating, especially by means of amplitudedemodulation and/or by means of frequency demodulation, informationconcerning at least one physical, measured variable and/or thedistributor module from an electrical carrier signal transmitted via aninductively coupling interface, wherein, for forming an inductivelycoupling interface transmitting, especially simultaneously, data as wellas electrical energy, an input of the first demodulator is connected, atleast at times, especially predominantly or permanently, to one,especially exactly one, of the transformer coils. Developing thisembodiment of the invention further, it is additionally provided thatthe electronics module has at least a second demodulator for separatinginformation concerning at least one physical, measured variable and/orthe distributor module from an electrical carrier signal transmitted viaan inductively coupling interface, wherein, for forming an inductivelycoupling interface transmitting, especially simultaneously, data as wellas electrical energy, an input of the second demodulator is connected,at least at times, especially predominantly or permanently, to one,especially exactly one, of the transformer coils, especially thetransformer coil of the third connection system. Developing thisembodiment of the invention further, it is additionally provided thatthe electronics module has at least a third demodulator for separatinginformation concerning at least one physical, measured variable and/orthe distributor module from an electrical carrier signal transmitted viaan inductively coupling interface. In such a case, for forming aninductively coupling, first interface for transmitting, especiallysimultaneously, data as well as electrical energy, an input of the firstdemodulator can be connected, at least at times, especially permanently,to the transformer coil of the first connection system; for forming aninductively coupling, second interface for transmitting, especiallysimultaneously, data as well as electrical energy, an input of thesecond demodulator can be connected, at least at times, especiallypermanently, to the transformer coil of the second connection system;and for forming an inductively coupling, third interface fortransmitting, especially simultaneously, data as well as electricalenergy, an input of the third demodulator can be connected, at least attimes, especially permanently, to the transformer coil of the thirdconnection system.

According to a third embodiment of the distributor module of theinvention, it is provided that the electronics module has at least afirst modulator for modulating, especially by means of amplitudemodulation and/or frequency modulation, information concerning the atleast one physical, measured variable and/or measuring devices onto anelectrical carrier signal transmittable via an inductively couplinginterface wherein, for forming an inductively coupling interfacetransmitting, especially simultaneously, data as well as electricalenergy, an output of the first modulator is connected, at least attimes, especially predominantly or permanently, to one, especiallyexactly one, of the transformer coils. Developing this embodiment of theinvention further, it is additionally provided that the electronicsmodule has at least a second modulator for modulating informationconcerning the at least one physical, measured variable and/or measuringdevices onto an electrical carrier signal transmittable via aninductively coupling interface, wherein, for forming an inductivelycoupling interface transmitting, especially simultaneously, data as wellas electrical energy, an output of the second modulator is connected, atleast at times, to one of the transformer coils. Developing thisembodiment of the invention further, it is additionally provided thatthe electronics module has at least a third modulator for modulatinginformation concerning at least one physical, measured variable and/orthe distributor module onto an electrical carrier signal transmittablevia an inductively coupling interface. In such a case, for forming aninductively coupling, first interface for transmitting, especiallysimultaneously, data as well as electrical energy, an output of thefirst modulator can be connected, at least at times, especiallypermanently, to the transformer coil of the first connection system; forforming an inductively coupling, second interface for transmitting,especially simultaneously, data as well as electrical energy, an outputof the second modulator can be connected, at least at times, especiallypermanently, to the transformer coil of the second connection system;and for forming an inductively coupling, third interface fortransmitting, especially simultaneously, data as well as electricalenergy, an output of the third modulator can be connected, at least attimes, especially permanently, to the transformer coil of the thirdconnection system

According to a fourth embodiment of the distributor module theinvention, it is provided that the electronics module has at least afirst modem, operated especially in semi-duplex or full-duplex mode, forseparating, especially by means of amplitude demodulation and/or bymeans of frequency demodulation, information relevant to the at leastone physical, measured variable from an electrical carrier signaltransmitted via an inductively coupling interface and for modulating,especially by means of amplitude modulation and/or by means of frequencymodulation, information concerning the at least one physical, measuredvariable and/or measuring devices onto an electrical carrier signal tobe transmitted via an inductively coupling interface, wherein, forforming an inductively coupling interface transmitting, especiallysimultaneously, data as well as electrical energy, a first input of thefirst modem is connected, at least at times, with one of the transformercoils and a first output of the first modem is connected, at least attimes, with said transformer coil. Developing this embodiment of theinvention further, it is additionally provided that the electronicsmodule has at least a second modem for separating, especially by meansof amplitude demodulation and/or by means of frequency demodulation,information relevant to the at least one physical, measured variablefrom an electrical carrier signal transmitted via an inductivelycoupling interface and for modulating, especially by means of amplitudemodulation and/or by means of frequency modulation, informationconcerning the at least one physical, measured variable and/or measuringdevices onto an electrical carrier signal to be transmitted via aninductively coupling interface; wherein, for forming an inductivelycoupling interface transmitting, especially simultaneously, data as wellas electrical energy, a first input of the second modem is connected, atleast at times, to one of the transformer coils and a first output ofthe second modem is connected, at least at times, with said transformercoil. Developing this embodiment of the invention further, it isadditionally provided that the electronics module has at least a thirdmodem for separating, especially by means of amplitude demodulationand/or frequency demodulation, information concerning the at least onephysical, measured variable from an electrical carrier signaltransmitted via an inductively coupling interface and for modulating,especially by means of amplitude modulation and/or frequency modulation,information concerning the at least one physical, measured variableand/or measuring devices onto an electrical carrier signal to betransmitted via an inductively coupling interface; wherein, for formingan inductively coupling interface transmitting, especiallysimultaneously, data as well as electrical energy, a first input of thethird modem is connected, at least at times, to one of the transformercoils and a first output of the third modem is connected, at least attimes, to said transformer coil. In such a case, a second input of thethird modem is coupled at least at times, especially permanently, to anoutput of the control unit; and/or a second output of the third modem iscoupled at least at times, especially permanently, to an input of thecontrol unit.

According to a fifth embodiment of the distributor module of theinvention, it is provided that the electronics module has an internalsupply circuit coupled at least at times, especially permanently, withat least one of the transformer coils, especially an internal supplycircuit having a capacitive and/or inductive and/or electrochemical,energy storer for providing electrical energy transmittable via aninductively coupling interface. Developing this embodiment of theinvention further, it is additionally provided that the internal supplycircuit provides electrical energy transmittable via an inductivelycoupling interface by means of an alternating electrical current,especially, a sinusoidal or rectangular, alternating electrical current,driven via an alternating voltage, especially an impressed, alternatingvoltage and/or an alternating voltage held at a predetermined voltagelevel. The alternating voltage and/or the alternating electrical currentcan serve, in such case, for forming a carrier signal for informationtransmittable via an inductively coupling interface. In another furtherdevelopment of the fifth embodiment of the distributor module of theinvention, it is additionally provided that the internal supply circuitis connected during operation simultaneously, especially permanently, totransformer coils of at least two connection systems; and/or that theinternal supply circuit has at least one rectifier, which iselectrically connected, at least at times, to at least one of thetransformer coils via a primary side voltage connection for alternatingvoltage; and/or that the internal supply circuit (NRG) has at least oneinverter, which is electrically connected, at least at times, to atleast one of the transformer coils via a secondary side voltageconnection for alternating voltage; and/or that the internal supplycircuit has at least one electrical current converter which iselectrically connected, at least at times, to at least one of thetransformer coils via a voltage connection for alternating voltage;and/or that the internal supply circuit has at least one frequencyconverter, which is electrically connected, at least at times, to atleast one of the transformer coils, especially the transformer coil ofthe first connection system, via a first voltage connection foralternating voltage and which is electrically connected, at least attimes, to at least one of the transformer coils, especially thetransformer coil of the third connection system, via a second voltageconnection for alternating voltage.

According to a sixth embodiment of the distributor module of theinvention, it is provided that such further comprises:

-   -   At least one connection system, especially a connection system        constructed equally to the first connection system, for an        external service module, especially a service and/or diagnostic        unit; and/or    -   at least one connection system, especially a connection system        constructed equally to the first connection system, for an        external data memory, especially an EEPROM and/or a hard disk,        for storing measured variables and/or information concerning the        distributor module or measuring devices connected thereto;        and/or    -   further connection systems, especially connection systems        constructed equally to the first connection system, for each        measuring device delivering measured data.

According to a seventh embodiment of the distributor module of theinvention, it is provided that the module housing is embodied explosionprotectedly and/or pressure resistantly, especially in a mannersufficient to meet the requirements of the ignition protection type“Pressure-Resistant Encapsulation” (Ex-d); and/or that the electronicsmodule is embodied explosion protectedly, especially in a mannersufficient to meet the requirements of the ignition protection type“Intrinsic Safety” (Ex-i) and/or the requirements of the ignitionprotection type “Increased Safety” (Ex-e).

According to a first embodiment of the measuring system of theinvention, it is provided that such further comprises:

-   -   a first measuring device delivering, especially by means of an        alternating electrical current modulated as regards amplitude        and/or frequency and/or by means of an alternating voltage        modulated as regards amplitude and/or frequency, at least at        times, information, especially in the form of a telegram        according to a Universal Asynchronous Receiver Transmitter        protocol, concerning at least one physical, measured variable of        a first type and having a connection system for the distributor        module or for a connecting cable serving for connecting of        measuring device and distributor module, especially a cable        corresponding to one of the standard interfaces EIA-485, EIA-232        or EIA-422;    -   at least a second measuring device delivering, especially by        means of an alternating electrical current modulated as regards        amplitude and/or frequency and/or by means of an alternating        voltage modulated as regards amplitude and/or frequency, at        least at times, information, especially in the form of a        telegram according to a Universal Asynchronous Receiver        Transmitter protocol, concerning the measured variable of first        type and/or a physical, measured variable of second type and        having a connection system for the distributor module or for a        connecting cable serving for connecting of measuring device and        distributor module, especially a cable corresponding to one of        the standard interfaces EIA-485, EIA-232 or EIA-422; as well as    -   an electronic data processing unit, especially an electronic        data processing unit remote from the distributor module and/or        connected to a fieldbus, wherein the electronic data processing        unit is coupled electrically, with interpositioning of the        distributor module, at least at times, with the first measuring        device and/or with the second measuring device.

Further developing this embodiment of the measuring system of theinvention, it is additionally provided that at least one of themeasuring devices, especially each of the two measuring devices, issupplied with electrical energy at least partially by the distributormodule; and/or that at least one, especially each of the at least twomeasuring devices, in each case, draws electrical power convertedtherein at least partially from the distributor module via theconnection system of the distributor module connected to said measuringdevice; and/or that the first measuring device is connected to thedistributor module via a first connection system, especially byinterposing a connecting cable; and/or that the second measuring deviceis connected to the distributor module via a second connection system,especially by interposing a connecting cable.

According to a second embodiment of the measuring system of theinvention, it is provided that the connection system of at least one,especially each, of the at least two measuring devices includes, in eachcase, a transformer coil for forming an interface, which serves fortransmitting, especially simultaneously, data, especially by means ofthe Universal Asynchronous Receiver Transmitter protocol or ETHERNET, aswell as electrical energy, by inductive coupling, especially exclusivelyby inductive coupling, especially while also holding the at least onemeasuring device galvanically isolated from the distributor module.Developing this embodiment of the measuring system of the inventionfurther, it is additionally provided that the transformer coil of atleast one, especially each, of the at least two measuring devices isplaced within a plug connector element made at least partially,especially predominantly or exclusively, from a plastic or othersynthetic material, especially an electrically non conductive material,for forming a plug connector coupling, especially a releasable plugconnector coupling, wherein the plug connector element is embodiedcomplementarily to at least one of the plug connector elements of thedistributor module; and/or that the transformer coil of at least one,especially each, of the at least two measuring devices forms, togetherwith the, in each case, corresponding transformer coil of thedistributor module connection system connected to the particularmeasuring device, a transformer, especially a transformer implementingthe single electrical connection between said measuring device and thedistributor module.

According to a third embodiment of the measuring system of theinvention, it is provided that the first measuring device is connectedto the first connection system to form a first interface, which servesfor transmitting, especially simultaneously, data, especially by meansof the Universal Asynchronous Receiver Transmitter protocol, as well aselectrical energy, by inductive coupling, especially exclusively byinductive coupling, especially while also holding the first measuringdevice galvanically isolated from the distributor module, especiallyalso while forming a releasable plug connector coupling. Furtherdeveloping this embodiment of the measuring system of the invention, itis additionally provided that the second measuring device is connectedto the second connection system to form a second interface, which servesfor transmitting, especially simultaneously, data, especially by meansof the Universal Asynchronous Receiver Transmitter protocol, as well aselectrical energy, by inductive coupling, especially exclusively byinductive coupling, especially while also holding the second measuringdevice galvanically isolated from the distributor module, especiallyalso while forming a releasable plug connector coupling.

According to a fourth embodiment of the measuring system of theinvention, it is provided that at least one of the measuring devices isa pH-measuring device, which recurringly registers a pH value of aliquid; and/or that at least one of the measuring devices is aconductivity measuring device, which recurringly registers an electricalconductivity of a liquid; and/or that at least one the measuring devicesis a pressure measuring device, which recurringly registers a pressureof a fluid.

According to a fifth embodiment of the measuring system of theinvention, it is provided that at least one of the measuring devicescomprises a potentiometric sensor, an amperometric sensor, a photometricsensor, a spectrometric sensor, a temperature sensor, a pressure sensor,a flow sensor or a conductivity sensor.

According to a sixth embodiment of the measuring system of theinvention, it is provided that such further comprises a fieldbus,especially a FOUNDATION FIELDBUS or PROFIBUS fieldbus, on which theelectronic data processing unit sends, at least at times, a measuredvalue and/or a current operating state of the distributor module and/ora parameter value signaling one of the measuring devices connectedthereto.

According to a seventh embodiment of the measuring system of theinvention, it is provided that the distributor module is supplied atleast partially with electrical energy by the electronic data processingunit; and/or that the distributor module draws electrical powerconverted therein at least partially from the electronic data processingunit; and/or that the electronic data processing unit is connected tothe distributor module via a third connection system, especially byinterposing a connecting cable.

A basic idea of the invention is, among other things, to improvemeasuring systems by means of the distributor module of the inventiontoward the goal that, in the case of operationally related replacementof measuring devices on-site, an interruption free measuring operationis enabled, while maintaining the high process safety of inductivelycoupling interfaces of the type discussed above. Additionally, a furtheradvantage of the invention is also to be seen in the fact that by meansof the connection system of the distributor module, standard interfacescan be provided, which are, in given cases, also adaptable duringoperation and insofar universal, and which also enable the implementingof diverse measuring systems. thus measuring systems formed withmeasuring devices using different measurement principles, or, however,spatially distributed measuring systems with comparatively little wiringeffort. The connecting of such a modular, in given cases, alsoenergetically autarkic, measuring system to superordinated dataprocessing systems can be performed, in such a case, in advantageousmanner by applying plug connector systems already established inindustrial measurements technology, formed from plug connector elementscomplementary to one another, especially also plug connector elementslacking contacts, for instance, according to the above mentioned U.S.Pat. No. 6,705,898 or 6,476,520. Furthermore, repeater and/or switch, orhub, functionalities can be provided for industrial measurementstechnology by means of the distributor module of the invention.

The invention as well as other advantageous embodiments thereof will nowbe explained in greater detail based on examples of embodimentspresented in the figures of the drawing. Equal parts are provided withequal reference characters in all figures; in the interest ofperspicuity, previously mentioned reference characters are omitted insubsequent figures. Other advantageous embodiments or furtherdevelopment will become evident additionally from the dependent claims,as well as also from the figures of the drawing per se. The figures ofthe drawing show as follows:

FIG. 1 schematically, of a measuring system including a measuring deviceconnected to a distributor module as well as a data processing unitconnected to such distributor module;

FIGS. 2 to 5 embodiments of a distributor module suitable for ameasuring system according to FIG. 1; and

FIG. 6 a modem circuit (including rectifier) suitable for application insuch a distributor module.

FIG. 1 shows a measuring system for registering and forwarding measuredvalues. The measuring system comprises a first measuring device S1delivering, at least at times, information, coded in digitized measureddata, for example, concerning at least one physical, measured variablex1 of first type, especially serving for influencing and/or monitoring aprocess parameter of an industrial and/or automated process to bemonitored, as well as at least a second measuring device S2 delivering,at least at times, information concerning the physical, measuredvariable x1 of first type and/or information, coded in digitizedmeasured data, for example, concerning at least a physical, measuredvariable x2 of second type. For the latter case, the physical, measuredvariable x1 of first type can differ from the physical, measuredvariable x2 of second type, for example, as regards the location of theregistering sensors and/or as regards their dimensions. For example,serving as measuring devices S1, S2 can be a pH measuring devicerecurringly registering a pH value of a liquid, a conductivity measuringdevice recurringly registering an electrical conductivity of a liquid,or a pressure measuring device recurringly registering a pressure of afluid. Correspondingly, at least one of the measuring devices S1, S2 canbe equipped with a potentiometric sensor, an amperometric sensor, aphotometric sensor, a spectrometric sensor, a pressure sensor, or aconductivity sensor, while, of course, other measuring device types, andthus also other measuring transducer types, can also serve forimplementing the measuring system, such as, for instance, also a flowmeasuring flow measuring device or sensors, or also temperaturemeasuring devices or sensors. Furthermore, the particular measuringdevice S1, S2 can include, as is quite usual in such measuring systems,a microprocessor 7, as well as an analog-digital converter connectedthereto for digitizing an analog primary signal corresponding to theregistered measured variable and generated by the measuring transducer.The particular measuring device S1, S2 additionally comprises digitaldata memory, in which sensor data or process data can be stored. Forexample, calibration data for the respective measuring transducer canalso be stored in the digital data memory. With the help of thecalibration data, the digitized measured data delivered by the measuringtransducer can be converted to corresponding physical, measured values,also, in given cases, externally of the respective measuring device. Thecalibration values ascertained for the measuring transducer can bestored within the respective measuring device, thus enabling a fixedassociation of the calibration data with the measuring transducer. Sinceeach measuring device S1, S2 bears its own calibration data withinitself, confusion between different sets of calibration data can beprevented.

Additionally, the measuring system comprises a distributor module Vconnected to at least two measuring devices S1, S2 as well as anelectronic data processing unit NLU, especially one remote from thedistributor module and/or connected to a fieldbus. The electronic dataprocessing unit NLU is, at least at times, electrically coupled throughthe distributor module to the first measuring device S1 and/or to thesecond measuring device S2. Consequently, each of the at least twomeasuring devices includes a connection system for the distributormodule or for a connecting cable CC1, CC2, for example, a connectingcable corresponding to one of the standard interfaces EIA-485, EIA-232or EIA-422 mentioned above, serving to connect measuring device anddistributor module. The respective measuring device sends its measureddata RD_(S1), RD_(S2) via the connection system to the connecteddistributor module V, for example, in the form of an alternatingelectrical current modulated as regards amplitude and/or frequencyand/or by means of a alternating voltage modulated as regards amplitudeand/or frequency, or in the form of a telegram according to a UART(Universal Asynchronous Receiver Transmitter) protocol. The distributormodule in turn transmits the measured data further to data processingunit NLU via connecting cable CC3 connected to the distributor module.The data processing unit NLU is embodied, for example, in the form of ameasurement transmitter converting raw data to measured values. Theelectronic data processing unit NLU can be coupled, as presented in FIG.1, additionally to a fieldbus of the measuring system formed, forexample, as FOUNDATION FIELDBUS or PROFIBUS fieldbus, on which the dataprocessing unit transmits information TD_(NLU) transmitted from thedistributor module, information such as forwarded or conditionedmeasured data of the connected measuring devices and/or a currentoperating state of the distributor module and/or parameter valuessignaling one of the measuring devices connected thereto, or measuredvalues produced by the data processing unit from the received measureddata.

The distributor module V especially serves for distributing electricalpower to the at least two connected measuring devices S1, S2 as well asfor forwarding to the at least one superordinated electronic dataprocessing unit NLU information concerning the at least one physical,measured variable, sent on the part of the at least two connectedmeasuring devices. Especially, the data processing unit NLU serves alsofor processing data corresponding to the measured variable and/or forcontrolling the distributor module. As presented schematically in FIG.1, the distributor module comprises a module housing 200 (especially amodule housing 200 embodied to be water spray and/or explosion and/orpressure resistant), as well as an electronics module 100 (especially anexplosion protected, electronics module 100) placed within the modulehousing 200. Depending on the type of application selected, it canadditionally be required to construct the module housing to be explosionprotected and/or pressure resistant in a manner sufficient for therequirements according to the ignition protection type“Pressure-Resistant Encapsulation” (Ex-d) and/or to execute theelectronics module to be explosion protected in a manner sufficient forthe requirements according to the ignition protection type “IntrinsicSafety” (Ex-i) and/or the requirements according to the ignitionprotection type “Increased Safety” (Ex-e).

Furthermore, the distributor module includes a first connection systemA1 for the first measuring device S1 delivering, for example, digitizedmeasured data: a second connection system A2 for the second measuringdevice S2, delivering, for example, digitized measured data, as well asat least a third connection system A3 for the data processing unit NLU.Additionally, it can be quite an advantage, to provide other, especiallyconnection systems constructed equally to the first connection systemfor the distributor module, for example, in each case, for an additionalmeasuring device delivering measured data and/or for an external servicemodule, especially an operating and/or diagnostic unit and/or for anexternal data memory, especially an EEPROM and/or a hard disk for savingmeasured variables and/or relevant information from the distributormodule or measuring devices connected thereto.

For controlling the distributor module, especially also the firstconnection system and the second connection system and/or for processingcontrol commands received via a third connection system, the electronicsmodule according to an embodiment of the invention, as well as alsoschematically presented in FIGS. 1, 2, 3, 4, and 5, in each case,includes a control unit ALU, formed for example, by means of amicroprocessor (μC) and/or a modifiable logic chip (FPGA) and/or anapplication specific integrated circuit (ASIC).

Additionally, it can be quite advantageous further to provide thedistributor module with a display system HMI communicating with thecontrol unit, e.g. formed by means of a plurality of LEDs and/or adisplay, for visualizing data transmitted via the distributor moduleand/or for visualizing status information concerning the distributormodule, e.g. also instantaneous terminal assignments for connectionsystems of the distributor module and/or data streams flowing via theconnection system; and/or a servicing system HMI communicating with thecontrol unit, especially formed by means of individual keys and/or atouch display, for programming the control unit and/or for the selectiveturning on or off of connection systems of the distributor module;and/or a radio system WLAN communicating with the control unit forwireless sending and/or receiving of configuration data for thedistributor module.

Furthermore, it is also possible to equip the electronics module with anon-permament, especially persistent data memory, especially an EEPROMand/or a hard disk, communicating with the control unit and/orintegrated therein for the storing of measured variables and/or relevantinformation from the distributor module or measuring devices connectedthereto; for example, for the storing of measured values generated by ameasuring device connected to the distributor module, in given casesalso measured values marked with a time stamp representing the point intime of the generating; and/or for the storing of data identified forthe distributor module by a connected measuring device; and/or for thestoring of data, especially sensor type identification, authenticating aconnected measuring device in relation to the distributor module; and/orcalibration data specifying the sensor module; and/or certificatesfilled out for the measuring device; and/or operating approval grantedto the measuring device; and/or an enabling code serving for theactivation of the measuring device, and/or with at least one especiallypermanent data memory PROM, for example, for the storing of dataidentifying the distributor module for a connected measuring device;and/or data authenticating the distributor module in relation to themeasuring device; and/or for the storing data serving for aparameterization of a connected measuring device; and/or for the storingof certificates filled out for the distributor module; and/or foroperating approval granted to the distributor module, and/or for thestoring of an enabling code serving for the activation of the measuringdevice.

At least the two connection systems A1, A2, especially ones constructedequally to one another, provided for the measuring devices additionallyhave, in the case of the distributor module V of the invention, in eachcase, a transformer coil A1+, A2+ placed within the module housing,connected to the electronics module for forming an especially digital,inductively coupling interface transmitting data especially according tothe Universal Asynchronous Receiver Transmitter protocol (UART) as wellas electrical energy, in given cases also simultaneously, between therespective measuring device and the distributor module. In such a case,each of the at least two transformer coils A1+, A2+ of the distributormodule is placed, in each case, within an plug connector element A1#,A2# at least partially, especially predominantly or exclusively, of aplastic or other synthetic material, especially an electrically nonconductive material, serving to form a plug connector coupling,especially a releasable coupling, formed especially as an integralcomponent of the module housing. Additionally, the third connectionsystem provided for the data processing unit NLU includes, as presentedschematically in FIG. 1, a transformer coil A3+ placed within a plugconnector element A3# made at least partially, especially predominantlyor exclusively, of a plastic or other synthetic material, especially anelectrically non-conductive material, serving for the formation of aplug connector coupling, especially a releasable coupling, especiallyformed as an integral component of the module housing. For the caseshown here, in which the so formed interface has an exclusivelyinductively coupling nature, a galvanic isolation of the measuringdevice from the distributor module and in given cases, also of thedistributor module from the data processing unit can be achieved in avery simple manner. Furthermore, an interface impervious to liquids canbe implemented in a simple manner, in which no exposed contact elementsfor the manufacture of electrical connections between the measuringdevice and distributor module are required.

The respective measuring device is connected by means of the plugconnector element—here provided by the respective connecting cable CC1or CC2—by the plugging in of the same to the complementary plugconnector element of the distributor module V. In such a case, thetransformer coil of the relevant connection system and the associatedtransformer coil of the measuring device or its connecting cable areplaced in a defined spatial position relative to one another, so thathigh frequency carrier signals, also bi directional signals in givencases, can be transmitted between the distributor module V and eachconnected measuring device. In this way, data exchange between thedistributor module and the measuring device is enabled. Moreover, theenergy supply of the respective measuring device can also occur via theinductive interface. Conversely, the distributor module V can draw therequired energy from the connected data processing unit.

For separating information RD_(S1), RD_(S2), or RD_(NLU) concerning atleast one physical, measured variable and/or the distributor module froman electrical carrier signal transmitted via inductively couplinginterface, the electronics module includes at least one demodulatorDEMOD (correspondingly adapted to the modulation method actually appliedfor the received data), of which, for the purpose of forming theinductively coupling interface transmitting, especially simultaneously,data as well as electrical energy, one input is connected, at least attimes, especially predominantly or permanently, with, especiallyexactly, one of the transformer coils. A possible embodiment of ademodulator (here only passively implementing an amplitude demodulationof an input supplied, carrier signal carrying information RD_(x)(RD_(S1), RD_(S2), . . . , RD_(NLU))) is schematically shown in FIG. 6.Instead a demodulator implementing amplitude demodulation can, in caserequired, of course, be applied, as well as also a demodulatorimplementing another demodulation method, for example, a frequencydemodulation.

Additionally, the electronics module includes at least one modulator MODfor modulating information TD_(S1), TD_(S2), or TD_(NLU) concerning theat least one physical, measured variable and/or measuring devices ontoan electrical carrier signal transmittable via inductively couplinginterface, for example, by means of amplitude modulation (AM, ASK)and/or by means of frequency modulation (FM, FSK). For the purpose offorming the inductively coupling interface transmitting, especiallysimultaneously, data as well as electrical energy, an output of themodulator is connected, at least at times, especially predominantly orpermanently, with, especially exactly, one of the transformer coils. Apossible embodiment of a modulator (here implementing an amplitudedemodulation of an input supplied, carrier signal carrying informationTD_(x) (TD_(S1), TD_(S2), . . . , TD_(NLU))) is schematically shown inFIG. 6. Instead of such a modulator implementing an amplitudemodulation, for example, according to an amplitude shift keying (ASK),in case required, of course, also a modulator implementing anothermodulation method, for example, a frequency modulation according to afrequency shift keying method (FSK), can be applied.

Although modulator and demodulator can be embodied directly as separateassemblies, it is additionally, however, also directly possible toimplement these two functions, as well as also shown in FIGS. 2, 3, 4and 5, by means of a modem MODEM, operated e.g. in semi-duplex orfull-duplex mode, thus, especially a modem with integrated duplexerDPLX. For forming a data as well as electrical energy transmitting(especially simultaneously), inductively coupling interface, then aninput of the modem is, at least at times, connected with one of thetransformer coils and an output of the modem, at least at times, withthe same transformer coil.

Communication between the data processing unit NLU, the distributormodule V and the respective measuring device can occur in semi-duplexoperation, such as e.g. according to EIA-485, especially in the case ofapplication of serial, data interfaces. This means that information istransmitted either in the form of data RD_(NLU) from the data processingunit NLU via the distributor module V and in the form of data TD_(S1),TD_(S2) to the respective measuring device or, however, in reversedirection, in the form of data RD_(S1), or RD_(S2) from a measuringdevice via the distributor module V and in the form of data TD_(NLU) tothe data processing unit NLU. The particular transmission direction can,as shown e.g. in FIG. 6, be specified by a direction signal COM_(DIR),which is produced, for example, by the control unit provided in thedistributor module V and correspondingly fed to the duplexer DPLX.

Especially in the case of application only of a single modem for thetargeted, in given cases, bi-directional, transmission of informationbetween the data processing unit and the at least two measuring devices,a correspondingly matched control of the actually present, numeroussignal paths, or of a selective read-out of measured data received viaconnection system, or of a selective marking of data to transmit viaconnection system is required. Accordingly, the electronics module in anadditional embodiment includes a selective switching circuit SELECT, forexample, one controlled by the control unit ALU and/or integrated intosuch, for the selective connecting of the control unit to at least oneof the transformer coils, for example, according to the variant of thedistributor module shown in FIG. 2, and/or for the selective connectingof the third connection system to at least one of the transformer coilsof the first, or second, connection system, for example, according tothe variant of the distributor module shown in FIG. 3. Additionally, itis, however, directly also possible, as shown in FIG. 4 or 5, to assigneach of the connection systems A1, A2, A3 its own modem or, however,also by means of individual addressing inserted into the data telegrams,directly to access, or to query, from the data processing unit, allconnected measuring devices via a single modem of the distributormodule. Depending on application of the selective switching circuitSELECT within the signal path formed by means of the distributor module,this can function as a multiplexer switching a number of its inputssequentially to one output or as a demultiplexer switching one inputsequentially to a number of outputs.

In the case of the examples of embodiments shown in FIG. 3, the controlunit ALU of the distributor module 3 is practically itegrated into thesignal path extending between data processing unit NLU and the, in eachcase, addressed measuring device. The modem, or the demodulator,receives accordingly the carrier signal lying on the respectiveconnection system with the correspondingly on-modulated information. Theinformation separated by demodulation and thereafter coded in aUART-capable, digital data signal is fed to a corresponding UART-port ofthe control unit ALU. This forwards the so won information, for example,in turn, by means of an UART-capable digital data signal,correspondingly to the modulator, which is instantaneously connectedwith the connection system connected to the data processing unit.Insofar, the distributor module inserted in the signal path actspractically as a signal regenerator, which transmits a newlyreconditioned digital signal received at the input. Therefore, thedistributor module can serve in this case practically as a repeater formeasured data delivered by the measuring devices, or also for the datasent by the data processing unit to an, in each case, addressedmeasuring device, in which case noise as well as distortions are removedfrom the received digital signal and the digital signal is, thus,reconditioned as regards clocking and edge steepness. A worsening of thesignal quality along the transmission path can, thus, be counteracted bymeans of distributor module and possible defects in the signal qualityas a result of external disturbances or also as a result of attenuationbrought about by the connecting cable-, or travel time effects, as, forinstance, deteriorated edges, defective clocking and/or increased signalnoise, can, thus, be compensated. Thus, data processing unit, and,respectively, the measuring devices received data signals of high signalquality, whereby the frequency of transmission errors can be reduced.

For providing electrical power required for operation of the distributormodule and, in given cases, also connected measuring devices, theelectronics module includes, additionally, an internal supply circuitNRG coupled, at least at times, in given cases, also permanently, to atleast one of the transformer coils. Supply circuit NRG can include, forexample, also capacitive and/or inductive and/or electrochemical, energystorers. Supply circuit NRG provides electrical energy transmittable viainductively coupling interface and/or drawn via inductively couplinginterface, for example, electrical energy in the form of an alternatingcurrent, especially a sinusoidal or rectangular, alternating current,driven by an alternating voltage, especially an impressed alternatingvoltage and or an alternating voltage held at a predetermined voltagelevel. The alternating voltage and/or the alternating electrical currentcan serve for forming a carrier signal for information transmittable viainductively coupling interface. The information is correspondinglymodulated by means of the at least one modulator MOD, or by the modem.The internal supply circuit NRG can be connected, for example,permanently or, however, also via electronic switching network, only attimes to the transformer coils; in latter case, principally, however, insuch a manner, that the supply circuit is connected during operationsimultaneously to transformer coils of at least two connection systems.Furthermore, it can be necessary to provide in the supply circuit thecurrent limiter and/or voltage limiter for limiting maximum electricalpower issuable from its, in given cases, present, energy storer.

For obtaining, or providing, via connection system, incoming, andoutgoing, usable electrical energy, moreover, converter known to thoseskilled in the art can be used, such as, for instance, rectifiers AC/DCelectrically connected with a primary side voltage connection foralternating voltage, at least at times, to at least one of thetransformer coils, inverters DC/AC electrically connected with asecondary side voltage connection for alternating voltage, at least attimes, to at least one of the transformer coils, electrical currentconverters electrically connected with a voltage connection foralternating voltage, at least at times, to at least one of thetransformer coils, or frequency converters electrically connected with afirst voltage connection for alternating voltage, at least at times, toat least one of the transformer coils, especially the transformer coilof the first connection system, and with a second voltage connection foralternating voltage electrically connected, at least at times, to atleast one of the transformer coils, especially the transformer coil ofthe third connection system. In the latter case, for example, afrequency converter can be used, which is electrically connected with aprimary side first voltage connection for alternating voltage, at leastat times, to the transformer coil of the third connection system andwith a secondary side second voltage connection for alternating voltage,at least at times, especially in the case of connected first voltageconnection for alternating voltage to the transformer coil of the thirdconnection system, to the transformer coil of the first connectionsystem, and which, during operation, by means of a primary sidealternating voltage applied to its first voltage connection, delivers asecondary side alternating voltage of predeterminable frequency and/orpredeterminable amplitude applied to its second voltage connection,especially in such a manner, that the frequency of the secondary sidealternating voltage equals a frequency of the primary side alternatingvoltage and/or that the amplitude of the secondary side alternatingvoltage equals an amplitude of the primary side alternating voltage. Theinternal supplying of the distributor module with electrical power canthen occur directly by means of the output of the mentioned rectifierAC/DC, or by means of the direct voltage UN present in the intermediatecircuit of the frequency converter, or a direct voltage UN derivedtherefrom and a direct current IN correspondingly driven thereby.

A possible embodiment of an inverter DC/AC (here implemented by means ofa so-called class-E-amplifier) is schematically shown in FIG. 6. Theparticular inverter DC/AC can be correspondingly activated, for example,by means of a control signal NRG_(ACT) delivered by the, in given cases,provided, control unit ALU. With application of a measuring circuitmonitoring the electrical current I_(x) (I_(S1), I_(S2), . . . )actually flowing on the output, or with application of a correspondingmonitoring signal NRG_(DIAG) delivered therefrom corresponding with theelectrical current I_(X), additionally, during operation, by means ofthe control unit, it can recurringly be detected, whether a measuringdevice S1, S2, . . . . Is actually connected to the particularconnection system A1, A2 . . . . In case, based on a too low electricalcurrent I_(X), it is recognized, that the particular connection systemA1, A2, . . . is not supplied with a measuring device, such can beturned off for preventing further energy losses. As, among other things,shown in the initially mentioned German patent application102007020823.7, a class E amplifier can, with exploitation of itssectionally linear frequency response, be used also for the amplitudemodulation, especially also for amplitude shift keying (ASK) and,insofar, the modulator can be embodied as an integral component of theinverter DC/AC.

Finally, it is to be noted that also the electrical coupling betweendistributor module and data processing unit, be it as regards the datatransmission or as regards the energy supply, essentially can beembodied equally to that between distributor module and the individualmeasuring devices. In case required, for connecting the distributormodule to the data processing unit, instead of an interface of the typebeing discussed implemented by means of connecting cables and plugconnector coupling, for example, however, also a connecting cableconnected via connection terminal fixedly with the distributor modulecan be used.

The invention claimed is:
 1. A measuring system for measuring at leastone physical and/or at least one chemical measured variable, comprising:a distributor module including: a module housing; an electronics moduleplaced within the module housing; a first connection system including afirst transformer coil and a first plug connector element, wherein thefirst transformer coil is connected with the electronics module and isplaced within the first plug connector element, wherein the first plugconnector element is formed as an integral component of the modulehousing and is composed of an electrically non-conductive plastic orsynthetic material, wherein the first connection system is embodied toinductively couple with a first measuring device a second connectionsystem including a second transformer coil and a second plug connectorelement, wherein the second transformer coil is connected with theelectronics module and is placed within the second plug connectorelement, wherein the second plug connector element is formed as anintegral component of the module housing and is composed of anelectrically non-conductive plastic or synthetic material, wherein thesecond connection system is embodied to inductively couple with a secondmeasuring device; and a third connection system including a thirdtransformer coil and a third plug connector element, wherein the thirdtransformer coil is connected with the electronics module and is placedwithin the third plug connector element, wherein the third plugconnector element is formed as an integral component of the modulehousing and is composed of an electrically non-conductive plastic orsynthetic material, wherein the third connection system is embodied toinductively couple with a superordinate data processing unit; a firstmeasuring device measuring at least one physical and/or at least onechemical measured variable, and having a transformer coil and a plugconnector element, wherein the transformer coil is disposed within theplug connector element, and the plug connector element is embodiedcomplementary to the first plug connector element of the distributormodule such that the plug connector element of the first measuringdevice and the first plug connector element of the distributor moduleform a releasable coupling, wherein the first measuring device isconnected to the distributor module via the first connection system toform a first interface that serves for transmitting digital data andelectrical energy by inductive coupling; and an superordinate dataprocessing unit having a transformer coil and a plug connector element,wherein the transformer coil is disposed within the plug connectorelement, and the plug connector element is embodied complementary to thethird plug connector element of the distributor module such that theplug connector element of the electronic data processing unit and thethird plug connector element of the distributor module form a releasablecoupling, wherein the electronic data processing unit is connected tothe distributor module via the third connection system to form a thirdinterface that serves for transmitting digital data and electricalenergy by inductive coupling, wherein the electronics module isconfigured to receive electrical energy via the third connection systemand distribute the received electrical energy to the first connectionsystem and to the second connection system, and wherein the electronicsmodule is further configured to route digital communicationbidirectionally between the third connection system and the firstconnection system and bidirectionally between the third connectionsystem and the second connection system.
 2. The measuring system asclaimed in claim 1, further comprising: a second measuring devicemeasuring at least one physical and/or at least one chemical measuredvariable, and having a transformer coil and a plug connector element,wherein the transformer coil is disposed within the plug connectorelement, and the plug connector element is embodied complementary to thesecond plug connector element of the distributor module such that theplug connector element of the second measuring device and the secondplug connector element of the distributor module form a releasablecoupling, wherein the second measuring device is connected to thedistributor module via the second connection system to form a secondinterface that serves for transmitting digital data and electricalenergy by inductive coupling.
 3. The measuring system as claimed inclaim 2, wherein: the second measuring device is a conductivitymeasuring device, which recurringly registers an electrical conductivityof a liquid; or the second measuring device is a pressure measuringdevice, which recurringly registers a pressure of a fluid.
 4. Themeasuring system as claimed in claim 2, wherein: the second measuringdevice includes a potentiometric sensor, an amperometric sensor, aphotometric sensor, a spectrometric sensor, a temperature sensor, apressure sensor, a flow sensor, or a conductivity sensor.
 5. Themeasuring system as claimed in claim 2, further comprising: a fieldbus,wherein the electronic data processing unit is communicatively connectedwith the fieldbus.
 6. The measuring system as claimed in claim 2,wherein said superordinate data processing unit is remote from thedistributor module and/or connected to a fieldbus.
 7. The measuringsystem as claimed in claim 1, wherein said electronics module isembodied to meet requirements of the ignition protection type “IntrinsicSafety” (Ex-i).
 8. The measuring system as claimed in claim 1, whereinthe first interface that serves for transmitting digital data andelectrical energy by inductive coupling is configured to transmit thedigital data and the electrical energy simultaneously, and wherein thethird interface that serves for transmitting digital data and electricalenergy by inductive coupling is configured to transmit the digital dataand the electrical energy simultaneously.
 9. The measuring systemclaimed in claim 1, wherein the module housing is embodied water spray-and/or explosion- and/or pressure resistantly in a manner meetingrequirements of ignition protection type “Pressure-ResistantEncapsulation” (Ex-d).